1
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Joseph O, Eberle M, Lieberman M. Metabolites in Urine that Interfere with the Sandell-Kolthoff Assay for Urinary Iodine. Biol Trace Elem Res 2024; 202:466-472. [PMID: 37222924 DOI: 10.1007/s12011-023-03710-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Accepted: 05/16/2023] [Indexed: 05/25/2023]
Abstract
The Sandell-Kolthoff (SK) assay is the main analytical method used to monitor population iodine nutrition in low- and middle-income countries. This assay can distinguish between populations that are iodine-deficient (median urinary iodine levels below 100 ppb), iodine-sufficient (median urinary iodine levels between 100 and 300 ppb), and iodine- excessive(median urinary iodine levels above 300 ppb). However, the analysis of urine samples with the SK reaction is technically challenging, partly because urine samples must be rigorously pretreated to remove interferents. In the literature, the only urinary metabolite that has been identified as an interferent is ascorbic acid. In this study, we used the microplate SK method to screen thirty-three of the major organic metabolites present in urine. We identified four previously unknown interferents: citric acid, cysteine, glycolic acid and urobilin. For each interferent, we investigated the following factors: (1) nature of interference-positive or negative, (2) threshold concentration for interference, and (3) possible mechanisms of interference. While this paper does not attempt to provide an exhaustive list of all interferents, knowledge of the main interferents allows for targeted removal.
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Affiliation(s)
- Ornella Joseph
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, USA
| | - Madeline Eberle
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, USA
| | - Marya Lieberman
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, USA.
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2
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Sebastiao M, Quittot N, Marcotte I, Bourgault S. Fluorescence Resonance Energy Transfer to Detect Plasma Membrane Perturbations in Giant Plasma Membrane Vesicles. Bio Protoc 2023; 13:e4838. [PMID: 37817901 PMCID: PMC10560696 DOI: 10.21769/bioprotoc.4838] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 07/30/2023] [Accepted: 08/03/2023] [Indexed: 10/12/2023] Open
Abstract
Disruptions and perturbations of the cellular plasma membrane by peptides have garnered significant interest in the elucidation of biological phenomena. Typically, these complex processes are studied using liposomes as model membranes-either by encapsulating a fluorescent dye or by other spectroscopic approaches, such as nuclear magnetic resonance. Despite incorporating physiologically relevant lipids, no synthetic model truly recapitulates the full complexity and molecular diversity of the plasma membrane. Here, biologically representative membrane models, giant plasma membrane vesicles (GPMVs), are prepared from eukaryotic cells by inducing a budding event with a chemical stressor. The GPMVs are then isolated, and bilayers are labelled with fluorescent lipophilic tracers and incubated in a microplate with a membrane-active peptide. As the membranes become damaged and/or aggregate, the resulting fluorescence resonance energy transfer (FRET) between the two tracers increases and is measured periodically in a microplate. This approach offers a particularly useful way to detect perturbations when the membrane complexity is an important variable to consider. Additionally, it provides a way to kinetically detect damage to the plasma membrane, which can be correlated with the kinetics of peptide self-assembly or structural rearrangements. Key features • Allows testing of various peptide-membrane interaction conditions (peptide:phospholipid ratio, ionic strength, buffer, etc.) at once. • Uses intact plasma membrane vesicles that can be prepared from a variety of cell lines. • Can offer comparable throughput as with traditional synthetic lipid models (e.g., dye-encapsulated liposomes).
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Affiliation(s)
- Mathew Sebastiao
- Department of Chemistry, Université du Québec à Montréal, Montréal, QC, Canada
- PROTEO, Quebec Network for Research on Protein Function, Engineering, and Applications, Montréal, QC, Canada
| | - Noé Quittot
- Harvard Medical School, Boston, MA, USA
- Alzheimer Research Unit, Department of Neurology, Massachusetts General Hospital, Charlestown, MA, USA
| | - Isabelle Marcotte
- Department of Chemistry, Université du Québec à Montréal, Montréal, QC, Canada
- PROTEO, Quebec Network for Research on Protein Function, Engineering, and Applications, Montréal, QC, Canada
| | - Steve Bourgault
- Department of Chemistry, Université du Québec à Montréal, Montréal, QC, Canada
- PROTEO, Quebec Network for Research on Protein Function, Engineering, and Applications, Montréal, QC, Canada
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3
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Matson RS. Well-Based Multiplex Food Allergen Colorimetric ELISA. Methods Mol Biol 2023; 2612:169-181. [PMID: 36795367 DOI: 10.1007/978-1-0716-2903-1_13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
Food allergy is a well-recognized and significant health hazard around the world. At least 160 food groups have been identified that present allergenic reactions or other sensitivities and intolerance in humans. Enzyme-linked immunosorbent assay (ELISA) is an accepted platform for identifying the nature of the food allergy and its severity. It is now possible to simultaneously screen patients for allergic sensitivity and intolerance to multiple allergens using multiplex immunoassays. This chapter describes the preparation and utility of a multiplex allergen ELISA for the assessment of food allergy and sensitivity in patients.
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4
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Smith NJ, Maddahfar M, Gunasegaran B, McGuire HM, Fazekas de St Groth B. A High-Throughput Colorimetric Microplate Assay for Determination of Plasma Arginase Activity. Methods Mol Biol 2023; 2620:273-286. [PMID: 37010770 DOI: 10.1007/978-1-0716-2942-0_29] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/04/2023]
Abstract
Arginase, an enzyme involved in the urea cycle, is gaining attention as a critical player in numerous chronic pathologies. Additionally, increased activity of this enzyme has been shown to correlate with poor prognosis in a range of cancers. Colorimetric assays that measure the conversion of arginine to ornithine have long been used to determine the activity of arginase. However, this analysis is hindered by a lack of standardization across protocols. Here, we describe in detail a novel revision of the Chinard's colorimetric assay used to determine arginase activity. Dilution series of patient plasma are plotted to form a logistic function, from which activity can be interpolated by comparison to an ornithine standard curve. Inclusion of patient dilution series rather than a single point increases the robustness of the assay. This high-throughput microplate assay analyzes 10 samples per plate to produce highly reproducible results.
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5
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McNab E, Rether A, Hsiang T. Development of a microplate absorbance assay for assessing fungicide sensitivity of filamentous fungi and comparison to an amended agar assay. J Microbiol Methods 2023; 204:106653. [PMID: 36503052 DOI: 10.1016/j.mimet.2022.106653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 12/06/2022] [Accepted: 12/06/2022] [Indexed: 12/13/2022]
Abstract
Assessment of the sensitivity of non-sporulating fungi to fungicides through amended-media assays is labor intensive. As an alternative, we developed an absorbance assay using 96-well microplates to assess the sensitivity of Clarireedia jacksonii, a non-sporulating fungus, to the fungicide propiconazole based on the change in absorbance corresponding to fungal growth. This microplate assay can allow for the assessment of multiple isolates of C. jacksonii at different concentrations of a fungicide with many technical replications in a single plate. Three methods for inoculating microplate wells were compared. The "microplug" method was the simplest to perform, requiring only a micropipette with 1 ml tips. EC50 values from this microplate assay were compared to those of a traditional amended agar assay using 30 isolates of C. jacksonii with varying sensitivity to propiconazole. The non-transformed relationship between the two assays was low but weakly significant (R2 = 0.137, p = 0.037). However, correlation of log10 transformed EC50 values from both assays revealed a stronger and highly significant relationship (R2 = 0.56, p < 0.001). Additionally, the microplate assay appears to be more sensitive in detecting resistance (EC50 > 0.1 μg/ml), and revealed five of the assessed isolates to be resistant to propiconazole that were not found as such with the amended agar assay. These results imply that EC50 results from the microplate assay were not exactly equivalent to the amended agar assay for estimating EC50 values, but it may be useful in assigning or confirming general sensitivity classifications.
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Affiliation(s)
- Edward McNab
- School of Environmental Sciences, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Andrea Rether
- School of Environmental Sciences, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Tom Hsiang
- School of Environmental Sciences, University of Guelph, Guelph, Ontario N1G 2W1, Canada.
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6
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Tuncay A, Noble A, Guille M, Cobley JN. RedoxiFluor: A microplate technique to quantify target-specific protein thiol redox state in relative percentage and molar terms. Free Radic Biol Med 2022; 181:118-129. [PMID: 35131446 PMCID: PMC8904371 DOI: 10.1016/j.freeradbiomed.2022.01.023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 01/12/2022] [Accepted: 01/23/2022] [Indexed: 12/12/2022]
Abstract
Unravelling how reactive oxygen species regulate fundamental biological processes is hampered by the lack of an accessible microplate technique to quantify target-specific protein thiol redox state in percentages and moles. To meet this unmet need, we present RedoxiFluor. RedoxiFluor uses two spectrally distinct thiol-reactive fluorescent conjugated reporters, a capture antibody, detector antibody and a standard curve to quantify target-specific protein thiol redox state in relative percentage and molar terms. RedoxiFluor can operate in global mode to assess the redox state of the bulk thiol proteome and can simultaneously assess the redox state of multiple targets in array mode. Extensive proof-of-principle experiments robustly validate the assay principle and the value of each RedoxiFluor mode in diverse biological contexts. In particular, array mode RedoxiFluor shows that the response of redox-regulated phosphatases to lipopolysaccharide (LPS) differs in human monocytes. Specifically, LPS increased PP2A-, SHP1-, PTP1B-, and CD45-specific reversible thiol oxidation without changing the redox state of calcineurin, PTEN, and SHP2. The relative percentage and molar terms are interpretationally useful and define the most complete and extensive microplate redox analysis achieved to date. RedoxiFluor is a new antibody technology with the power to quantify relative target-specific protein thiol redox state in percentages and moles relative to the bulk thiol proteome and selected other targets in a widely accessible, simple and easily implementable microplate format.
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Affiliation(s)
- Ahmet Tuncay
- Redox Biology Group, UHI, Inverness, IV2 3JH, UK
| | - Anna Noble
- European Xenopus Resource Centre, University of Portsmouth, Portsmouth, PO1 2DY, UK
| | - Matthew Guille
- European Xenopus Resource Centre, University of Portsmouth, Portsmouth, PO1 2DY, UK
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7
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Pazdzior R, Kubicek S. PlateFlo - A software-controllable plate-scale perfusion system for culture of adherent cells. HardwareX 2021; 10:e00222. [PMID: 35607664 PMCID: PMC9123465 DOI: 10.1016/j.ohx.2021.e00222] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 07/23/2021] [Accepted: 08/05/2021] [Indexed: 06/15/2023]
Abstract
Here we present a versatile system for milliliter-scale perfusion culture of adherent cells that can be built using basic tools, based on a readily available one-well culture plate (84 cm2 culture area). Media composition and flow paths can be programmatically controlled via USB serial interface using the FETbox hardware controller and associated PlateFlo Python package. The FETbox can control up to five high current 12 V devices such as common pinch valves, solenoids, and DC motor peristaltic pumps. It was designed to be easily customized with built-in accommodation for additional electronic components (e.g. analog sensors and input), use of the ubiquitous Arduino Nano platform, and easily expanded serial communication protocol. Multiple FETboxes can be used in parallel for additional devices. Applications of the PlateFlo system include perfusion culture of laboratory experiments requiring large cell numbers including genome-scale genetic screens and proteomics, as well as novel perfusion schemes including dynamic media conditions and sequential cell culture.
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Key Words
- Adherent
- Automation
- BOM, bill of materials
- CFD, computational fluid dynamics
- Cell culture
- DMEM, Dulbecco’s modified Eagle’s medium
- EUR, Euro
- FDM, fused deposition modelling
- MCU, microcontroller unit
- MOSFET, metal oxide semiconductor field effect transistor
- Microplate
- Millifluidic
- PBS, phosphate-buffered saline
- PCB, printed circuit board
- PWM, pulse width modulation
- Perfusion
- hIPSC, human induced pluripotent stem cell
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8
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Kundert K. Wellmap: a file format for microplate layouts. BMC Res Notes 2021; 14:164. [PMID: 33933133 PMCID: PMC8088706 DOI: 10.1186/s13104-021-05573-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Accepted: 04/15/2021] [Indexed: 11/10/2022] Open
Abstract
Objective Microplates are ubiquitous in biological research because they make it easy to collect data for hundreds of different conditions in a single experiment. Despite this, there is no standard method to annotate the wealth of data contained in each plate. Results We introduce a new file format, called wellmap, for describing the layout of wells on microplates. The format is text-based and emphasizes being easy to read, write, and share. It is capable of describing any layout for any experiment. It is also accompanied by a tool for generating clear visualizations of layout files, and a simple API for parsing layout files in analysis scripts written in python or R. We have used wellmap in our own research to annotate data from a wide variety of experiments, including qPCR and flow cytometry. Given the large number of experiments that make use of microplates, it is our hope that other researchers will find this file format as useful as we have. For complete instructions on how to install and use wellmap, visit: https://wellmap.rtfd.io.
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Affiliation(s)
- Kale Kundert
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, 02138, USA.
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9
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Aktas GB, Ribera A, Skouridou V, Masip L. DNA immobilization and detection using DNA binding proteins. Anal Bioanal Chem 2021; 413:1929-1939. [PMID: 33501551 DOI: 10.1007/s00216-021-03162-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 12/29/2020] [Accepted: 01/06/2021] [Indexed: 10/22/2022]
Abstract
The immobilization of sensing bioreceptors is a critical feature affecting the final performance of a biosensor. For DNA detection, the (strept)avidin-biotin affinity interaction is often used for the immobilization of biotin-labeled oligonucleotides or PCR amplicons. Herein, DNA binding proteins are proposed as alternative universal anchors for both DNA immobilization and detection, based on the strong and specific affinity interaction between certain DNA binding proteins and their respective dsDNA binding sites. These binding sites can be incorporated in the target DNA molecule during synthesis and by PCR, eliminating the need for post-synthesis chemical modification and resulting in lower costs. When scCro DNA binding protein was immobilized on microplates and nitrocellulose membrane, both ssDNA and dsDNA targets were successfully detected. The detection limits achieved were similar to those obtained with the streptavidin-biotin system. However, the scCro system resulted in higher signals while using less amount of protein. The adsorption properties of scCro were superior to streptavidin's, making scCro a viable alternative as an anchor biomolecule for the development of DNA assays and biosensors. Finally, a nucleic acid lateral flow assay based solely on two different DNA binding proteins, scCro and dHP, was developed for the detection of a PCR amplicon. Overall, the proposed system appears to be very promising and with potential use for multiplex detection using various DNA binding proteins with different sequence specificities. Further work is required to better understand the adsorption properties of these biomolecules on nitrocellulose, optimize the assays comprehensively, and achieve improved sensitivities.
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Affiliation(s)
- Gülsen Betül Aktas
- Departament d'Enginyeria Química, Universitat Rovira i Virgili, 26 Països Catalans, 43007, Tarragona, Spain
| | - Arnau Ribera
- Departament d'Enginyeria Química, Universitat Rovira i Virgili, 26 Països Catalans, 43007, Tarragona, Spain
| | - Vasso Skouridou
- Departament d'Enginyeria Química, Universitat Rovira i Virgili, 26 Països Catalans, 43007, Tarragona, Spain
| | - Lluis Masip
- Departament d'Enginyeria Química, Universitat Rovira i Virgili, 26 Països Catalans, 43007, Tarragona, Spain.
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10
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Abstract
Multiplex immunoassays are important tools in basic research and diagnostics. The ability to accurately quantify the presence of several antigens within an individual sample all at once has been useful in developing a proteomics view of biology. This in turn has enabled the development of disease-associated immunodiagnostic panels for better prognosis and well-being. Moreover, it is well understood that such multiplexing approaches lend themselves to automation, thereby reducing labor while providing the ability to dramatically conserve both reagent and sample all of which will reduce the cost per test. Here we describe various methods to create and use multiplex immunoassays in the wells of microtiter plates or similar formats.
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11
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Abstract
In this reported work, we achieved high-throughput, highly sensitive fluorescent analysis using an enzyme-linked immunosorbent assay (ELISA) that employed a metallic nanoparticle (NP)-immobilized 96-well plate. The immobilization of metallic NPs on a 96-well plate effectively amplified fluorescent signals of the assay. The silver (Ag) NP-immobilized plate showed the best fluorescent enhancement effect of all plates immobilized by metal NPs. Our results demonstrate the potential of applying Ag NPs to enhance the efficiency of direct and indirect ELISA by the labeling of targets.
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Affiliation(s)
- Shuyi Sun
- Department of Applied Chemistry, Osaka Prefecture University
| | - Kyohei Matsui
- Department of Applied Chemistry, Osaka Prefecture University
| | - So Tanabe
- Department of Applied Chemistry, Osaka Prefecture University
| | - Dung Nguyen
- Department of Applied Chemistry, Osaka Prefecture University
| | | | - Yojiro Yamamoto
- Department of Applied Chemistry, Osaka Prefecture University.,GreenChem. Inc
| | - Hiroshi Shiigi
- Department of Applied Chemistry, Osaka Prefecture University
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12
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Higashitsuji Y, Ueno R, Ogawa M, Ruzicka D. Effects of Culture Conditions ( Microplate and Solvent) on in vitro Antifungal Activity of Caspofungin Against Candida Species. Med Mycol J 2020; 61:1-5. [PMID: 32115443 DOI: 10.3314/mmj.19-00012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Effects of the type of microplates and solvent for preparation of caspofungin (CPFG) on antifungal susceptibility testing of CPFG against clinical isolates of Candida albicans, Candida glabrata, and Candida krusei (20 strains each) by broth microdilution method according to the Clinical and Laboratory Standards Institute were evaluated. When CPFG was dissolved in water, MICs against the three Candida species decreased 3.1-6.0-fold in surface-untreated microplates compared to those in treated microplates. When CPFG was dissolved in dimethyl sulfoxide, MICs against the three Candida species decreased 1.3-2.5-fold in surface-untreated microplates compared to those in treated microplates. Differences in MICs according to the type of solvent did not exceed the difference for one dilution interval (0.5-2-fold MIC ratio) regardless of whether the microplate surface was treated or not. These findings suggest that differences in CPFG MICs may depend mainly on the type of surface treatment of assay microplates.
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13
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Allkja J, Bjarnsholt T, Coenye T, Cos P, Fallarero A, Harrison JJ, Lopes SP, Oliver A, Pereira MO, Ramage G, Shirtliff ME, Stoodley P, Webb JS, Zaat SAJ, Goeres DM, Azevedo NF. Minimum information guideline for spectrophotometric and fluorometric methods to assess biofilm formation in microplates. Biofilm 2019; 2:100010. [PMID: 33447797 PMCID: PMC7798448 DOI: 10.1016/j.bioflm.2019.100010] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 11/08/2019] [Accepted: 11/10/2019] [Indexed: 12/11/2022] Open
Abstract
The lack of reproducibility of published studies is one of the major issues facing the scientific community, and the field of biofilm microbiology has been no exception. One effective strategy against this multifaceted problem is the use of minimum information guidelines. This strategy provides a guide for authors and reviewers on the necessary information that a manuscript should include for the experiments in a study to be clearly interpreted and independently reproduced. As a result of several discussions between international groups working in the area of biofilms, we present a guideline for the spectrophotometric and fluorometric assessment of biofilm formation in microplates. This guideline has been divided into 5 main sections, each presenting a comprehensive set of recommendations. The intention of the minimum information guideline is to improve the quality of scientific communication that will augment interlaboratory reproducibility in biofilm microplate assays.
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Affiliation(s)
- Jontana Allkja
- LEPABE - Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465, Porto, Portugal.,Montana State University, Center for Biofilm Engineering, 366 Barnard Hall, Bozeman, MT, 59717, USA
| | - Thomas Bjarnsholt
- Department of Clinical Microbiology, Rigshospitalet, 2100, Copenhagen, Denmark.,Department of Immunology and Microbiology, Costerton Biofilm Center, Faculty of Health Sciences University of Copenhagen, 2200, Copenhagen, Denmark.,ESCMID Study Group for Biofilms, Basel, Switzerland
| | - Tom Coenye
- ESCMID Study Group for Biofilms, Basel, Switzerland.,Laboratory of Pharmaceutical Microbiology, Ghent University, Ghent, Belgium
| | - Paul Cos
- Laboratory for Microbiology, Parasitology and Hygiene (LMPH), Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, University of Antwerp, Antwerp, Belgium
| | - Adyary Fallarero
- Pharmaceutical Design and Discovery (PharmDD), Division of Pharmaceutical Biosciences, Faculty of Pharmacy, University of Helsinki, Viikinkaari 5E, P.O. Box 56, FI-00014, Helsinki, Finland
| | - Joe J Harrison
- Department of Biological Sciences, University of Calgary, 2500 University Drive NW, Calgary, AB, T2N 1N4, Canada
| | - Susana P Lopes
- Centre of Biological Engineering (CEB), Laboratório de Investigação Em Biofilmes Rosário Oliveira (LIBRO), University of Minho, Braga, Portugal
| | - Antonio Oliver
- Servicio de Microbiología, Hospital Universitario Son Espases, Instituto de Investigación Sanitaria Illes Balears (IdISBa), Palma de Mallorca, Spain
| | - Maria Olivia Pereira
- Centre of Biological Engineering (CEB), Laboratório de Investigação Em Biofilmes Rosário Oliveira (LIBRO), University of Minho, Braga, Portugal
| | - Gordon Ramage
- Oral Sciences Research Group, University of Glasgow Dental School, School of Medicine, Dentistry and Nursing, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom.,ESCMID Study Group for Biofilms, Basel, Switzerland
| | - Mark E Shirtliff
- Department of Microbial Pathogenesis, School of Dentistry, University of Maryland, Baltimore, MD, 21201, USA
| | - Paul Stoodley
- Department of Microbial Infection and Immunity and Orthopedics, The Ohio State University, Columbus, OH, 43210, USA.,National Centre for Advanced Tribiology at Southampton (nCATS), Department of Mechanical Engineering, University of Southampton, Southampton, SO17 1BJ, UK.,National Biofilms Innovation Centre, School of Biological Sciences, University of Southampton, Southampton, SO17 1BJ, UK
| | - Jeremy S Webb
- National Biofilms Innovation Centre, School of Biological Sciences, University of Southampton, Southampton, SO17 1BJ, UK
| | - Sebastian A J Zaat
- Amsterdam UMC, University of Amsterdam, Department of Medical Microbiology, Amsterdam Infection and Immunity Institute, Meibergdreef 9, 1105AZ, Amsterdam, the Netherlands
| | - Darla M Goeres
- Montana State University, Center for Biofilm Engineering, 366 Barnard Hall, Bozeman, MT, 59717, USA
| | - Nuno Filipe Azevedo
- LEPABE - Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465, Porto, Portugal
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14
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Hussain MT, Forbes N, Perrie Y, Malik KP, Duru C, Matejtschuk P. Freeze-drying cycle optimization for the rapid preservation of protein-loaded liposomal formulations. Int J Pharm 2019; 573:118722. [PMID: 31705976 DOI: 10.1016/j.ijpharm.2019.118722] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 09/14/2019] [Accepted: 09/20/2019] [Indexed: 02/02/2023]
Abstract
Technology such as the use of microfluidics to generate liposomes has been well researched, yet the stabilisation of liposomal formulations is a major challenge to their greater implementation. To the best of our knowledge, this is the first study investigating the use of 96 well plates to freeze-dry ovalbumin (OVA) loaded neutral (DMPC:Chol and DSPC:Chol), anionic (DSPC:Chol:PS) and cationic (DSPC:Chol:DOTAP) liposomes. Through the use of high throughput screening, a freeze drying cycle was optimised; ramp freezing from from 4 °C to -45 °C, followed by primary drying at -30 °C and secondary drying at 30 °C under a vacuum of 0.1 mBar. These parameters maintained liposome physicochemical properties, with the liposomes remaining below 100 nm and were homogenous (polydispersity index of less than 0.2 post rehydration). Minimal leakage of the OVA protein was observed, with almost 100% OVA remaining encapsulated post rehydration of the formulations. Here we have identified a simple method that allows for the rapid screening and freeze-drying of a range of liposomal formulations.
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Affiliation(s)
- Maryam T Hussain
- Strathclyde Institute of Pharmacy and Biomedical Science, University of Strathclyde, Glasgow G4 0RE, Scotland, United Kingdom
| | - Neil Forbes
- Strathclyde Institute of Pharmacy and Biomedical Science, University of Strathclyde, Glasgow G4 0RE, Scotland, United Kingdom
| | - Yvonne Perrie
- Strathclyde Institute of Pharmacy and Biomedical Science, University of Strathclyde, Glasgow G4 0RE, Scotland, United Kingdom
| | - Kiran P Malik
- Standardisation Science, National Institute for Biological Standards & Control (NIBSC), Blanche Lane, South Mimms, Potters Bar EN6 3QG, United Kingdom
| | - Chinwe Duru
- Standardisation Science, National Institute for Biological Standards & Control (NIBSC), Blanche Lane, South Mimms, Potters Bar EN6 3QG, United Kingdom
| | - Paul Matejtschuk
- Standardisation Science, National Institute for Biological Standards & Control (NIBSC), Blanche Lane, South Mimms, Potters Bar EN6 3QG, United Kingdom.
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15
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Beswick P, Wahab B, Honey MA, Paradowski M, Jiang K, Lochner M, Murrell-Lagnado RD, Thompson AJ. A challenge finding P2X1 and P2X4 ligands. Neuropharmacology 2019; 157:107674. [PMID: 31238045 DOI: 10.1016/j.neuropharm.2019.107674] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 05/24/2019] [Accepted: 06/17/2019] [Indexed: 01/09/2023]
Abstract
Identifying novel small-molecule P2X1 and P2X4 ligands with sub-type specificity and high-affinity remains a pharmacological challenge. Here we use computational methods, electrophysiology and fluorescent microplate assays to screen for ligand candidates acting at these receptors. Modelling and docking identified 80 compounds for testing at P2X4 receptors, and 20 of these showed >50% inhibition in fluorescence-based assays, making them appealing for further SAR studies. Confirmation of activity by two-electrode voltage clamp, followed by their elaboration resulted in only minor improvements in potency, with the highest IC50 being 295 μM. Testing on P2X1 receptors, resulted in a series of biguanide compounds that yielded a maximum IC50 of 100 μM, but no consistent SAR could be found. Potencies of established antagonists gave expected results, although the measured potencies varied between techniques and no antagonism could be found for compounds such as paroxetine, carbamazepine, 9(10H)-acridanone, acridinol and phenoxazine-type heterocycles. This study highlights the challenge of identifying P2X4 and P2X1 ligands and suggests that a combination of complimentary approaches is needed if we are to be confident of ligand activities at these receptors.
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Affiliation(s)
- Paul Beswick
- Sussex Drug Discovery Centre, School of Life Sciences, University of Sussex, Brighton, UK
| | - Ben Wahab
- Sussex Drug Discovery Centre, School of Life Sciences, University of Sussex, Brighton, UK
| | - Mark A Honey
- Sussex Drug Discovery Centre, School of Life Sciences, University of Sussex, Brighton, UK
| | | | - Ke Jiang
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bühlstrasse 28, 3012, Bern, Switzerland
| | - Martin Lochner
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bühlstrasse 28, 3012, Bern, Switzerland
| | - Ruth D Murrell-Lagnado
- Sussex Drug Discovery Centre, School of Life Sciences, University of Sussex, Brighton, UK
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Hanson KM, Finkelstein JN. An accessible and high-throughput strategy of continuously monitoring apoptosis by fluorescent detection of caspase activation. Anal Biochem 2019; 564-565:96-101. [PMID: 30365977 DOI: 10.1016/j.ab.2018.10.022] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Revised: 09/28/2018] [Accepted: 10/21/2018] [Indexed: 01/05/2023]
Abstract
We present a real-time, high-throughput, and cost-effective method of detecting apoptosis in vitro using a previously developed reagent that detects caspase activation by fluorescence. Current methods of assessing apoptosis fail to account for the dimension of time, and thus are limited in data yielded per sample. This reagent allows real-time detection of apoptosis, but until now has been restricted to a costly automated detection system. Here, we describe apoptosis detection with the Essen Bioscience IncuCyte® Caspase-3/7 Reagent using a multimode microplate reader, a common instrument in biological laboratories, which may be used prior to or in lieu of the automated system. This modified microplate reader apoptosis assay was validated against the established automated system, and was shown to detect a strong dose-response relationship (automated system r2 = 0.9968, microplate reader r2 = 0.9924). We also propose a quick and reliable method of quantifying cell density by Hoechst 33342 nuclear staining in microplates (r2 = 0.8812 between Hoechst signal and cell density). We assert that the dimension of time should not be overlooked, and that the method presented here is an accessible strategy for many researchers due to low startup cost and precise detection of apoptosis in real time.
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17
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Rahier R, Abla H, Arhab Y, Noiriel A, Abousalham A. Direct and Continuous Measurement of Phospholipase D Activities Using the Chelation-Enhanced Fluorescence Property of 8-Hydroxyquinoline. Methods Mol Biol 2018; 1835:129-38. [PMID: 30109649 DOI: 10.1007/978-1-4939-8672-9_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
Phospholipase D (PLD) hydrolyzes phospholipids to form phosphatidic acid (PA) and the corresponding headgroup. To date, PLD has been linked to several pathologies, such as cancer, making this enzyme an important therapeutic target. However, most PLD assays developed so far are either discontinuous or based on the indirect determination of choline released upon phosphatidylcholine (PC) hydrolysis. Therefore, we designed a PLD assay that is based on the chelation-enhanced fluorescence property of 8-hydroxyquinoline. This assay exhibits a strong fluorescence signal upon Ca2+ complexation with the PLD-generated PA and is not limited to PC as the substrate but allows the use of natural phospholipids with various headgroups. Besides, this easy-to-handle assay allows to monitor prokaryotic and eukaryotic PLD activities in a continuous way and on a microplate scale.
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18
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Sardella D, Gatt R, Valdramidis VP. Turbidimetric Assessment of the Growth of Filamentous Fungi and the Antifungal Activity of Zinc Oxide Nanoparticles. J Food Prot 2018; 81:934-941. [PMID: 29745759 DOI: 10.4315/0362-028x.jfp-17-448] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Rapid assessment of fungal growth and screening antifungal compounds, such as nanoparticles (NPs), for effectiveness is a challenging procedure because no primary standards exist as they do for yeasts and bacteria. Because fungi do not grow as single cells, but as hyphal filaments, they cannot be quantified by the usual enumeration techniques used in bacteriology. The growth of three postharvest fungal isolates ( Alternaria alternata, Rhizopus stolonifer, and Botrytis cinerea) was investigated at different inoculum concentrations and in three nutrient media (Sabouraud dextrose agar, potato dextrose agar, and yeast extract dextrose agar [YED]) with a turbidimetric assay. Sequential measurements were performed to generate optical density versus time plots, whereas the growth responses were expressed quantitatively as the generated trapezoidal area. YED medium showed the lowest variation among replicated experiments; potato dextrose agar showed the next lowest, but there was no significant difference. The inoculum size had a minimal effect on the variation of the fungal dynamics. Microscopic assessment of the fungal growth confirmed that YED medium allowed the most homogeneous development of the studied fungi. Therefore, we developed a rapid and reliable technique to evaluate the efficacy of novel antifungal compounds such as zinc oxide NPs. Turbidimetric assessment showed that these NPs were able to inhibit the growth of all three isolates. A. alternata and B. cinerea did not show a significant difference in the level of inhibition at 15 mM, whereas R. stolonifer showed the highest inhibition at the same concentration.
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Affiliation(s)
- Davide Sardella
- 1 Department of Food Sciences and Nutrition, Faculty of Health Science, University of Malta, Triq Dun Karm, L-Imsida, MSD 2080, Malta.,2 Centre for Molecular Medicine and Biobanking, University of Malta, Triq Dun Karm, L-Imsida, MSD 2080, Malta
| | - Ruben Gatt
- 3 Metamaterials Unit, Faculty of Science, University of Malta, Triq Dun Karm, L-Imsida, MSD 2080, Malta
| | - Vasilis P Valdramidis
- 1 Department of Food Sciences and Nutrition, Faculty of Health Science, University of Malta, Triq Dun Karm, L-Imsida, MSD 2080, Malta.,2 Centre for Molecular Medicine and Biobanking, University of Malta, Triq Dun Karm, L-Imsida, MSD 2080, Malta
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19
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Arora NK, Verma M. Modified microplate method for rapid and efficient estimation of siderophore produced by bacteria. 3 Biotech 2017; 7:381. [PMID: 29109926 DOI: 10.1007/s13205-017-1008-y] [Citation(s) in RCA: 90] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Accepted: 10/09/2017] [Indexed: 12/20/2022] Open
Abstract
In this study, siderophore production by various bacteria amongst the plant-growth-promoting rhizobacteria was quantified by a rapid and efficient method. In total, 23 siderophore-producing bacterial isolates/strains were taken to estimate their siderophore-producing ability by the standard method (chrome azurol sulphonate assay) as well as 96 well microplate method. Production of siderophore was estimated in percent siderophore unit by both the methods. It was observed that data obtained by both methods correlated positively with each other proving the correctness of microplate method. By the modified microplate method, siderophore production by several bacterial strains can be estimated both qualitatively and quantitatively at one go, saving time, chemicals, making it very less tedious, and also being cheaper in comparison with the method currently in use. The modified microtiter plate method as proposed here makes it far easier to screen the plant-growth-promoting character of plant-associated bacteria.
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20
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Fakruddin M, Hossain MN, Ahmed MM. Evaluation of microplate immunocapture method for detection of Vibrio cholerae, Salmonella Typhi and Shigella flexneri from food. BMC Microbiol 2017; 17:189. [PMID: 28851288 PMCID: PMC5576308 DOI: 10.1186/s12866-017-1099-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Accepted: 08/22/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Improved methods with better separation and concentration ability for detection of foodborne pathogens are in constant need. The aim of this study was to evaluate microplate immunocapture (IC) method for detection of Salmonella Typhi, Shigella flexneri and Vibrio cholerae from food samples to provide a better alternative to conventional culture based methods. RESULTS The IC method was optimized for incubation time, bacterial concentration, and capture efficiency. 6 h incubation and log 6 CFU/ml cell concentration provided optimal results. The method was shown to be highly specific for the pathogens concerned. Capture efficiency (CE) was around 100% of the target pathogens, whereas CE was either zero or very low for non-target pathogens. The IC method also showed better pathogen detection ability at different concentrations of cells from artificially contaminated food samples in comparison with culture based methods. Performance parameter of the method was also comparable (Detection limit- 25 CFU/25 g; sensitivity 100%; specificity-96.8%; Accuracy-96.7%), even better than culture based methods (Detection limit- 125 CFU/25 g; sensitivity 95.9%; specificity-97%; Accuracy-96.2%). CONCLUSION The IC method poses to be the potential to be used as a method of choice for detection of foodborne pathogens in routine laboratory practice after proper validation.
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Affiliation(s)
- Md Fakruddin
- Industrial Microbiology Laboratory, Institute of Food Science and Technology (IFST), Bangladesh Council of Scientific and Industrial Research (BCSIR), Dhaka, 1205, Bangladesh.
| | - Md Nur Hossain
- Industrial Microbiology Laboratory, Institute of Food Science and Technology (IFST), Bangladesh Council of Scientific and Industrial Research (BCSIR), Dhaka, 1205, Bangladesh
| | - Monzur Morshed Ahmed
- Industrial Microbiology Laboratory, Institute of Food Science and Technology (IFST), Bangladesh Council of Scientific and Industrial Research (BCSIR), Dhaka, 1205, Bangladesh
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21
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Abstract
Determination of cellular neutral lipid levels in yeast is important for both the biotechnology industry and biomedical research. However, many of the currently available methods are labor intensive and time consuming. Here we describe a rapid and repeatable method for the detection of neutral lipids, which can be utilized in both oleaginous and non-oleaginous yeast species. The method utilizes the fluorescent dye, Nile red, which enables neutral lipid levels to either be visualized via microscopy or quantified using a 96-well plate assay.
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Affiliation(s)
- Kerry Ann Rostron
- School of Pharmacy and Biomedical Sciences, University of Central Lancashire, Preston, Lancashire, UK
- School of Biological Sciences, University of Reading, Reading, Berkshire, UK
| | - Clare Louise Lawrence
- School of Pharmacy and Biomedical Sciences, University of Central Lancashire, Preston, Lancashire, PR1 2HE, UK.
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22
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Costa SPF, Pinto PCAG, Lapa RAS, Saraiva MLMFS. Toxicity assessment of ionic liquids with Vibrio fischeri: an alternative fully automated methodology. J Hazard Mater 2015; 284:136-142. [PMID: 25463227 DOI: 10.1016/j.jhazmat.2014.10.049] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Revised: 10/16/2014] [Accepted: 10/31/2014] [Indexed: 06/04/2023]
Abstract
A fully automated Vibrio fischeri methodology based on sequential injection analysis (SIA) has been developed. The methodology was based on the aspiration of 75 μL of bacteria and 50 μL of inhibitor followed by measurement of the luminescence of bacteria. The assays were conducted for contact times of 5, 15, and 30 min, by means of three mixing chambers that ensured adequate mixing conditions. The optimized methodology provided a precise control of the reaction conditions which is an asset for the analysis of a large number of samples. The developed methodology was applied to the evaluation of the impact of a set of ionic liquids (ILs) on V. fischeri and the results were compared with those provided by a conventional assay kit (Biotox(®)). The collected data evidenced the influence of different cation head groups and anion moieties on the toxicity of ILs. Generally, aromatic cations and fluorine-containing anions displayed higher impact on V. fischeri, evidenced by lower EC50. The proposed methodology was validated through statistical analysis which demonstrated a strong positive correlation (P>0.98) between assays. It is expected that the automated methodology can be tested for more classes of compounds and used as alternative to microplate based V. fischeri assay kits.
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Affiliation(s)
- Susana P F Costa
- REQUIMTE, Departamento de Ciências Químicas, Faculdade de Farmácia, Universidade do Porto, Rua Jorge Viterbo Ferreira, n° 228, 4050-313 Porto, Portugal
| | - Paula C A G Pinto
- REQUIMTE, Departamento de Ciências Químicas, Faculdade de Farmácia, Universidade do Porto, Rua Jorge Viterbo Ferreira, n° 228, 4050-313 Porto, Portugal.
| | - Rui A S Lapa
- REQUIMTE, Departamento de Ciências Químicas, Faculdade de Farmácia, Universidade do Porto, Rua Jorge Viterbo Ferreira, n° 228, 4050-313 Porto, Portugal
| | - M Lúcia M F S Saraiva
- REQUIMTE, Departamento de Ciências Químicas, Faculdade de Farmácia, Universidade do Porto, Rua Jorge Viterbo Ferreira, n° 228, 4050-313 Porto, Portugal.
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Duellman T, Burnett J, Yang J. Quantitation of secreted proteins using mCherry fusion constructs and a fluorescent microplate reader. Anal Biochem 2014; 473:34-40. [PMID: 25542417 DOI: 10.1016/j.ab.2014.12.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Revised: 12/12/2014] [Accepted: 12/16/2014] [Indexed: 12/14/2022]
Abstract
Traditional assays for secreted proteins include methods such as Western blot and enzyme-linked immunosorbent assay (ELISA) detection of the protein in the cell culture medium. We describe a method for the detection of a secreted protein based on fluorescent measurement of an mCherry fusion reporter. This microplate reader-based mCherry fluorescence detection method has a wide dynamic range of 4.5 orders of magnitude and a sensitivity that allows detection of 1 to 2fmol fusion protein. Comparison with the Western blot detection method indicated greater linearity, wider dynamic range, and a similar lower detection threshold for the microplate-based fluorescent detection assay of secreted fusion proteins. An mCherry fusion protein of matrix metalloproteinase-9 (MMP-9), a secreted glycoprotein, was created and expressed by transfection of human embryonic kidney (HEK) 293 cells. The cell culture medium was assayed for the presence of the fluorescent signal up to 32 h after transfection. The secreted MMP-9-mCherry fusion protein was detected 6h after transfection with a linear increase in signal intensity over time. Treatment with chloroquine, a drug known to inhibit the secretion of many proteins, abolished the MMP-9-mCherry secretion, demonstrating the utility of this method in a biological experiment.
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Affiliation(s)
- Tyler Duellman
- Translational Cardiovascular Science Training Program, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA; Department of Anesthesiology, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA
| | - John Burnett
- Department of Anesthesiology, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA
| | - Jay Yang
- Translational Cardiovascular Science Training Program, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA; Department of Anesthesiology, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA.
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24
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Van Wagenen J, Holdt SL, De Francisci D, Valverde-Pérez B, Plósz BG, Angelidaki I. Microplate-based method for high-throughput screening of microalgae growth potential. Bioresour Technol 2014; 169:566-572. [PMID: 25103033 DOI: 10.1016/j.biortech.2014.06.096] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Revised: 06/24/2014] [Accepted: 06/26/2014] [Indexed: 05/21/2023]
Abstract
Microalgae cultivation conditions in microplates will differ from large-scale photobioreactors in crucial parameters such as light profile, mixing and gas transfer. Hence volumetric productivity (P(v)) measurements made in microplates cannot be directly scaled up. Here we demonstrate that it is possible to use microplates to measure characteristic exponential growth rates and determine the specific growth rate light intensity dependency (μ-I curve), which is useful as the key input for several models that predict P(v). Nannochloropsis salina and Chlorella sorokiniana specific growth rates were measured by repeated batch culture in microplates supplied with continuous light at different intensities. Exponential growth unlimited by gas transfer or self-shading was observable for a period of several days using fluorescence, which is an order of magnitude more sensitive than optical density. The microplate datasets were comparable to similar datasets obtained in photobioreactors and were used an input for the Huesemann model to accurately predict P(v).
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Affiliation(s)
- Jon Van Wagenen
- Technical University of Denmark, Department of Environmental Engineering, DTU Environment, Building 113, DK-2800 Kgs. Lyngby, Denmark.
| | - Susan Løvstad Holdt
- Technical University of Denmark, Department of Environmental Engineering, DTU Environment, Building 113, DK-2800 Kgs. Lyngby, Denmark
| | - Davide De Francisci
- Technical University of Denmark, Department of Environmental Engineering, DTU Environment, Building 113, DK-2800 Kgs. Lyngby, Denmark
| | - Borja Valverde-Pérez
- Technical University of Denmark, Department of Environmental Engineering, DTU Environment, Building 113, DK-2800 Kgs. Lyngby, Denmark
| | - Benedek Gy Plósz
- Technical University of Denmark, Department of Environmental Engineering, DTU Environment, Building 113, DK-2800 Kgs. Lyngby, Denmark
| | - Irini Angelidaki
- Technical University of Denmark, Department of Environmental Engineering, DTU Environment, Building 113, DK-2800 Kgs. Lyngby, Denmark.
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25
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Lau CY, Zahidi AAA, Liew OW, Ng TW. A direct heating model to overcome the edge effect in microplates. J Pharm Biomed Anal 2014; 102:199-202. [PMID: 25289516 DOI: 10.1016/j.jpba.2014.09.021] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Revised: 09/10/2014] [Accepted: 09/13/2014] [Indexed: 11/25/2022]
Abstract
Array-based tests in a microplate format are complicated by the regional variation in results of the outer against the inner wells of the plate. Analysis of the evaporation mechanics of sessile drops showed that evaporation rate increase with temperature was due to changes in the heat of vaporization, density and diffusion coefficient. In simulations of direct bottom heating of standard microplates, considerable heat transfer via conduction from the side walls was found to be responsible for lower temperatures in the liquid in wells close to the edge. Applying a two temperature heating mode, 304 K at the side compared to 310 K at the bottom, allowed for a more uniform temperature distribution. Transparency microplates were found to inherently possess immunity to the edge effect problem due to the presence of air between the liquid and solid wall.
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Affiliation(s)
- Chun Yat Lau
- Laboratory for Optics and Applied Mechanics, Department of Mechanical & Aerospace Engineering, Monash University, Clayton, Victoria 3800, Australia
| | - Alifa Afiah Ahmad Zahidi
- Laboratory for Optics and Applied Mechanics, Department of Mechanical & Aerospace Engineering, Monash University, Clayton, Victoria 3800, Australia
| | - Oi Wah Liew
- Cardiovascular Research Institute, Yong Loo Lin School of Medicine, National University of Singapore, National University Health System, Centre for Translational Medicine, 14 Medical Drive, Singapore 117599, Singapore
| | - Tuck Wah Ng
- Laboratory for Optics and Applied Mechanics, Department of Mechanical & Aerospace Engineering, Monash University, Clayton, Victoria 3800, Australia.
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Kaufman RC, Wilson JD, Bean SR, Herald TJ, Shi YC. Development of a 96-well plate iodine binding assay for amylose content determination. Carbohydr Polym 2014; 115:444-7. [PMID: 25439917 DOI: 10.1016/j.carbpol.2014.09.015] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2014] [Revised: 08/29/2014] [Accepted: 09/01/2014] [Indexed: 11/26/2022]
Abstract
Cereal starch amylose/amylopectin (AM/AP) is critical in functional properties for food and industrial applications. Conventional methods of AM/AP are time consuming and labor intensive making it difficult to screen the large sample sets necessary for evaluating breeding samples and investigating environmental impact on starch development. The objective was to adapt and optimize the iodine binding assay in a 96-well plate format for measurement at both λ 620 nm and λ 510 nm. The standard curve for amylose content was scaled to a 96-well plate format and demonstrated R(2) values of 0.999 and 0.993 for single and dual wavelengths, respectively. The plate methods were applicable over large ranges of amylose contents: high amylose maize starch at 61.7±2.3%, normal wheat starch at 29.0±0.74%, and a waxy maize starch at 1.2±0.9%. The method exhibited slightly greater amylose content values than the Concanavalin A method for normal type starches; but is consistent with cuvette scale iodine binding assays.
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Affiliation(s)
- R C Kaufman
- USDA-ARS Center for Grain and Animal Health Research, 1515 College Ave, Manhattan, KS, United States
| | - J D Wilson
- USDA-ARS Center for Grain and Animal Health Research, 1515 College Ave, Manhattan, KS, United States.
| | - S R Bean
- USDA-ARS Center for Grain and Animal Health Research, 1515 College Ave, Manhattan, KS, United States
| | - T J Herald
- USDA-ARS Center for Grain and Animal Health Research, 1515 College Ave, Manhattan, KS, United States
| | - Y-C Shi
- Department of Grain Science and Industry, Kansas State University, Manhattan, KS, United States
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27
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Kil HN, Eom SY, Park JD, Kawamoto T, Kim YD, Kim H. A rapid method for estimating the levels of urinary thiobarbituric Acid reactive substances for environmental epidemiologic survey. Toxicol Res 2014; 30:7-11. [PMID: 24795793 PMCID: PMC4007046 DOI: 10.5487/tr.2014.30.1.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Revised: 02/06/2014] [Accepted: 02/13/2014] [Indexed: 11/20/2022] Open
Abstract
Malondialdehyde (MDA), used as an oxidative stress marker, is commonly assayed by measuring the thiobarbituric acid reactive substances (TBARS) using HPLC, as an indicator of the MDA concentration. Since the HPLC method, though highly specific, is time-consuming and expensive, usually it is not suitable for the rapid test in large-scale environmental epidemiologic surveys. The purpose of this study is to develop a simple and rapid method for estimating TBARS levels by using a multiple regression equation that includes TBARS levels measured with a microplate reader as an independent variable. Twelve hour urine samples were obtained from 715 subjects. The concentration of TBARS was measured at three different wavelengths (fluorescence: λ-ex 530 nm and λ-ex 550 nm; λ-ex 515 nm and λ-ex 553 nm; and absorbance: 532 nm) using microplate reader as well as HPLC. 500 samples were used to develop a regression equation, and the remaining 215 samples were used to evaluate the validity of the regression analysis. The induced multiple regression equation is as follows: TBARS level (μM) = -0.282 + 1.830 × (TBARS level measured with a microplate reader at the fluorescence wavelengths λ-ex 530 nm and λ-em 550 nm, μM) -0.685 × (TBARS level measured with a microplate reader at the fluorescence wavelengths λ-ex 515 nm and λ-em 553 nm, μM) + 0.035 × (TBARS level measured with a microplate reader at the absorbance wavelength 532 nm, μM). The estimated TBARS levels showed a better correlation with, and are closer to, the corresponding TBARS levels measured by HPLC compared to the values obtained by the microplate method. The TBARS estimation method reported here is simple and rapid, and that is generally in concordance with HPLC measurements. This method might be a useful tool for monitoring of urinary TBARS level in environmental epidemiologic surveys with large sample sizes.
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Affiliation(s)
- Han-Na Kil
- Department of Preventive Medicine and Medical Research Institute, College of Medicine, Chungbuk National University, Cheongju, Korea ; Division of Biobank for Health Science, Center for Genome Science, Korea National Institute of Health, Korea Centers for Disease Control and Prevention, Osong, Korea
| | - Sang-Yong Eom
- Department of Preventive Medicine and Medical Research Institute, College of Medicine, Chungbuk National University, Cheongju, Korea
| | - Jung-Duck Park
- Department of Preventive Medicine, Chung-Ang University, College of Medicine, Seoul, Korea
| | - Toshihiro Kawamoto
- Department of Environmental Health, University of Occupational and Environmental Health, Kitakyushu, Japan
| | - Yong-Dae Kim
- Department of Preventive Medicine and Medical Research Institute, College of Medicine, Chungbuk National University, Cheongju, Korea
| | - Heon Kim
- Department of Preventive Medicine and Medical Research Institute, College of Medicine, Chungbuk National University, Cheongju, Korea
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Lau CY, Roslan Z, Cheong BH, Chua WS, Liew OW, Ng TW. Transparency microplates under impact. J Colloid Interface Sci 2014; 426:56-63. [PMID: 24863765 DOI: 10.1016/j.jcis.2014.03.048] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Accepted: 03/17/2014] [Indexed: 10/25/2022]
Abstract
Transparency microplates enable biochemical analysis in resource-limited laboratories. During the process of transfer, the analytes tittered into the wells may undergo spillage from one well to another due to lateral impact. Sidelong impact tests conducted found the absence of non-linear effects (e.g., viscoelastic behavior) but high energy loss. Finite element simulations conducted showed that the rectangular plate holding the transparencies could undergo z-axis deflections when a normal component of the force was present despite constraints being used. High speed camera sequences confirmed this and also showed the asymmetrical z-axis deflection to cause the contact line closer to impact to displace first when the advancing condition was exceeded. Capillary waves were found to travel toward the contact line at the opposite end, where if the advancing contact angle condition was exceeded, also resulted in spreading. The presence of surface scribing was found to limit contact line movement better. With water drops dispensed on scribed transparencies, immunity from momentum change of up to 9.07 kgm/s on impact was possible for volumes of 40 μL. In the case of glycerol drops immunity from momentum change of up to 9.07 kgm/s on impact extended to volumes of 90 μL. The improved immunity of glycerol was attributed to its heightened dampening characteristics and its higher attenuation of capillary waves. Overall, scribed transparency microplates were able to better withstand spillage from accidental impact. Accidental impact was also found not to cause any detrimental effects on the fluorescence properties of enhanced green fluorescent protein samples tested.
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Ortiz GE, Guitart ME, Albertó E, Fernández Lahore HM, Blasco M. Microplate assay for endo-polygalacturonase activity determination based on ruthenium red method. Anal Biochem 2014; 454:33-5. [PMID: 24613259 DOI: 10.1016/j.ab.2014.02.028] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2013] [Revised: 02/23/2014] [Accepted: 02/26/2014] [Indexed: 11/18/2022]
Abstract
Endo-polygalacturonase (endo-PGase) activity determinations generally rely on viscosity changes or reducing sugar ends produced by this activity over polygalacturonic acid. Torres and coworkers [Enzyme Microb. Technol. 48 (2011) 123-128] showed that ruthenium red (RR) is useful for endo-PGase determination. In this article, we present a high-throughput liquid-based endo-PGase assay based on the RR method and compare it with the viscosity determination method. The reduced assay uses a small volume of enzyme solution, 40 μg of polygalacturonic acid, and 45 μg of RR for each sample determination. Furthermore, we obtained an interconversion factor for RR and viscosity activities.
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Affiliation(s)
- Gastón E Ortiz
- Instituto de Investigaciones Biotecnológicas-Instituto Tecnológico Chascomús (IIB-INTECH, UNSAM-CONICET), Universidad de San Martín, San Martín, Buenos Aires 1650, Argentina
| | - María E Guitart
- Downstream Processing Laboratory, Jacobs University Bremen, D-28759 Bremen, Germany
| | - Edgardo Albertó
- Instituto de Investigaciones Biotecnológicas-Instituto Tecnológico Chascomús (IIB-INTECH, UNSAM-CONICET), Universidad de San Martín, San Martín, Buenos Aires 1650, Argentina
| | | | - Martin Blasco
- Instituto de Investigaciones Biotecnológicas-Instituto Tecnológico Chascomús (IIB-INTECH, UNSAM-CONICET), Universidad de San Martín, San Martín, Buenos Aires 1650, Argentina.
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Cui Z, Gilda JE, Gomes AV. Crude and purified proteasome activity assays are affected by type of microplate. Anal Biochem 2013; 446:44-52. [PMID: 24141075 DOI: 10.1016/j.ab.2013.10.018] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Revised: 10/04/2013] [Accepted: 10/10/2013] [Indexed: 11/18/2022]
Abstract
Measurement of proteasome activity is fast becoming a commonly used assay in many laboratories. The most common method to measure proteasome activity involves measuring the release of fluorescent tags from peptide substrates in black microplates. Comparisons of black plates used for measuring fluorescence with different properties show that the microplate properties significantly affect the measured activities of the proteasome. The microplate that gave the highest reading of trypsin-like activity of the purified 20S proteasome gave the lowest reading of chymotrypsin-like activity of the 20S proteasome. Plates with medium binding surfaces from two different companies showed an approximately 2-fold difference in caspase-like activity for purified 20S proteasomes. Even standard curves generated using free 7-amino-4-methylcoumarin (AMC) were affected by the microplate used. As such, significantly different proteasome activities, as measured in nmol AMC released/mg/min, were obtained for purified 20S proteasomes as well as crude heart and liver samples when using different microplates. The naturally occurring molecule betulinic acid activated the chymotrypsin-like proteasome activity in three different plates but did not affect the proteasome activity in the nonbinding surface microplate. These findings suggest that the type of proteasome activity being measured and sample type are important when selecting a microplate.
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Affiliation(s)
- Ziyou Cui
- Department of Neurobiology, Physiology, and Behavior, University of California, Davis, CA 95616, USA
| | - Jennifer E Gilda
- Department of Neurobiology, Physiology, and Behavior, University of California, Davis, CA 95616, USA
| | - Aldrin V Gomes
- Department of Neurobiology, Physiology, and Behavior, University of California, Davis, CA 95616, USA; Department of Physiology and Membrane Biology, University of California, Davis, CA 95616, USA.
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Esna-Ashari F, Shafyi A, Taqavian M, Mohammadi A, Sadigh Z, Sabiri G, Mirshahreza H, Hamzehloo Z, Taleblue F, Sheikh-Mohammadi N. Microtitration of rubella virus in monovalent vaccinal products. Iran J Public Health 2011; 40:68-71. [PMID: 23113057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/07/2010] [Accepted: 02/28/2011] [Indexed: 10/26/2022]
Abstract
BACKGROUND Potency test for control of rubella vaccine is a significant factor to qualify production line and vaccination program. For this reason, WHO recommends to use the microtitration method by both vaccine companies and control laboratories. Then the study was done to improve this test. METHODS Three rubella virus samples, including an in-house standard, a lot of vaccine and an in-process product, were tittered in cell culture tubes. Then micro titration steps were tested on 96-well microplate using cocultivation of standard rubella vaccine dilutions and RK-13 cell line. After 6-7 days, final reading was done and calculated the titer. Two other samples were assayed with the micromethod. RESULTS Titer reduction less than 0.5 log was acquired for each sample during frequent tests and between two methods. CONCLUSION The procedure was profitable and accurate for potency and identity tests of rubella virus vaccine, on the basis of WHO recommendations.
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